ASME B16.10 Pn60 Equipment Pressure Relief Spring Slightly Opened Closed Safety Valve

Product Description

Product Description

Spring-loaded normally open/closed safety valves are critical pressure relief devices engineered to protect industrial systems from overpressure hazards. Designed with a precision spring mechanism, these valves feature two configurable default states: normally open (NO) (maintaining an open position under standard conditions) or normally closed (NC) (remaining sealed until triggered).

Constructed from robust materials such as carbon steel, stainless steel, or alloy steel, they offer exceptional resistance to high temperatures, corrosion, and pressure fluctuations—suitable for handling liquids, gases, and steam across diverse industrial applications. The valve core integrates a spring-loaded disc that presses against a precision-machined seat, with the spring force pre-calibrated to match the system's maximum allowable working pressure (MAWP).

In normally closed configuration, the valve remains sealed during normal operation; when system pressure exceeds the pre-set threshold, it overcomes the spring force, lifting the disc to release excess pressure. For normally open models, the spring keeps the valve open to maintain continuous flow or ventilation, closing only when pressure drops below a specified level or external actuation is applied.

Equipped with adjustable spring tension for precise pressure setting, these valves ensure reliable overpressure protection and system stability. Ideal for chemical processing, power generation, water treatment, and pressure vessel systems, they combine robust performance, configurable operation, and leak-tight sealing to safeguard equipment and personnel.

Materialsformainparts
NO.	Name of part				A27H	Materials		A27W-P
1	Body				Ht350			ZG1Cr18Ni9Ti
2	Nozzle				35			ZG1Cr18Ni9Ti
3	Adjusting ring				20Cr13			1Cr18Ni9Ti
4	Disc				20Cr13			1Cr18Ni9Ti
5	Spring				50CrVA			50CrVA Coated
6	S t e m				20Cr13			20Cr13
7	Adjusting bolt				45			20Cr13
8	C a p				ZG200-400			ZG200-400
	Sealing surface of material				D507 Depositing D507			Depositing stellite

Dimensions(mm)
Nominal diameter DN(mm)		Dimensions(mm)
		do		Rc			L		Li
15		10		1/2"			40		65
20		15		3/4"			45		65
25		20		1"			45		76
32		25		1/."			55		85
40		32		17			55		90
50		40		2"			67		105
65		50		2'			76		128
80		65		3"			110		145

How does valve work?

Spring-loaded normally open/closed safety valves operate via a precision spring-and-disc mechanism, driven by system pressure to maintain safety or flow control, with two core configurable modes.

For normally closed (NC) models—most common for overpressure protection—the valve remains sealed under standard operation. A pre-calibrated high-grade spring exerts downward force on a precision-machined disc, pressing it tightly against the valve seat to block media flow. When system pressure rises above the pre-set maximum allowable working pressure (MAWP), the pressure force on the disc overcomes the spring’s tension. This lifts the disc off the seat, creating a passage to release excess pressure. Once pressure drops back to safe levels, the spring rebounds, pushing the disc back onto the seat to re-seal the valve, restoring normal operation.
For normally open (NO) configurations, the spring is calibrated to hold the disc in an open position during standard conditions, allowing continuous media flow or ventilation. The spring force keeps the disc lifted off the seat, ensuring unobstructed passage. The valve closes only when system pressure drops below a pre-determined threshold (e.g., in vacuum scenarios) or when external actuation (if equipped) overrides the spring force, pushing the disc onto the seat to block flow.
Many variants include adjustable spring tension to fine-tune pressure triggers. Built with corrosion-resistant materials (stainless steel, alloys) and tight-sealing seats, they operate reliably without external power, making them critical for pressure vessels, pipelines, and industrial systems requiring fail-safe protection.

Product Advantages

A – Adjustable Pressure Precision
Pre-calibrated spring tension with adjustable settings enables precise matching to system MAWP (Maximum Allowable Working Pressure). Ensures accurate pressure relief or flow control, avoiding under/over-actuation.

B – Bi-Configurable Operational Modes
Offers both normally open (NO) and normally closed (NC) configurations. Adapts to diverse system needs—continuous ventilation (NO) or overpressure protection (NC)—enhancing application flexibility.

C – Consistent Leak-Tight Sealing
Precision-machined disc and seating surfaces, paired with spring-loaded pressure, form a reliable seal. Prevents media leakage under standard operating conditions, safeguarding system efficiency and safety.

D – Durable Spring Mechanism
High-grade, corrosion-resistant springs maintain consistent force over time. Withstands high temperatures, pressure cycles, and harsh media, ensuring long-term operational reliability.

E – Emergency Overpressure Protection
Instantly triggers (for NC models) when pressure exceeds thresholds, releasing excess pressure to prevent equipment damage or system failure. Acts as a critical safety barrier for pressure vessels and pipelines.

F – Flexible Media Compatibility
Constructed from carbon steel, stainless steel, or alloys, handling liquids, gases, steam, and aggressive chemicals. Suitable for chemical processing, power generation, and water treatment industries.

G – Low-Maintenance & Self-Actuated
No external power required—operates via spring force and system pressure. Minimal moving parts reduce wear and maintenance needs, lowering long-term operational costs.